Marine biologist Matthias Kopfmiller wants to know whether the Wallace Line exists underwater. We descend deep into a subterranean crevice and shine a light on a universe that has never before been captured on film.
David Attenborough takes a breathtaking journey through the vast and diverse continent of Africa as it has never been seen before. (Part 3: Congo) The very heart of Africa is covered in dense tropical rainforest. The animals that live here find the most ingenious ways to carve out their space in a claustrophobic landscape. Danger lurks in every shadow, but some animals thrive here, from honey-stealing chimps to birds with a lineage as old as the dinosaurs, thundering elephants and kick-boxing frogs. Here in the Congo, no matter how tough the competition, you must stand up and fight for yourself and your patch.
Titus the gorilla king faces the biggest challenge of his life. He's lived longer and sired more offspring than any other known gorilla, but his time as a great leader may be coming to an end. The mighty silverback has a little orphan in his care - and both their lives hang in the balance. In Uganda, young silverback Marembo is back with his raging hormones and desire to be dominant - he's sure to shake things up a bit.
Bees and ants work selflessly toward a common goal. Bonobos maintain social harmony through sex, while meerkats organize themselves with military-level discipline. What do these creatures all have in common? The basic recognition that their survival hinges on an ability to work and live together.